What should you do if you see only a white light from a power-driven vessel at night?

If you see only a white light from a power-driven vessel at night, it indicates that you are overtaking that vessel. According to navigational rules, when a power-driven vessel is seen displaying only a white light, it means that you are likely approaching from behind and must understand your position in relation to that vessel. This observation is crucial for safe navigation, as it informs you of your responsibilities as the overtaking vessel.

In such a scenario, you would typically have the right of way to pass, but it is essential to ensure safe passing distance and conditions. Recognizing that you are overtaking allows you to proceed with caution while making the appropriate decisions about your speed and course.

The other options pertain to different circumstances or misunderstandings of the situation at hand. Being identified as the stand-on vessel is applicable in cases where two vessels are on a collision course, and one has the right of way. Signaling your intention to pass might be relevant when more than one vessel is in close proximity, but it is not a primary action required upon seeing only a single white light. Reducing speed immediately is typically not necessary unless safety dictates, rather, maintaining a safe speed to assess the situation is advisable.